In conventional vehicle automatic transmissions of the torque converter type, a driving shaft extends from the torque converter into the transmission housing to a unit therein having one or more clutch drums around which are arranged either single-wrap or double wrap brake bands. Depending on torque requirements, one-piece bands can be utilized in low load/torque coast band or overdrive situations. It is the function of the brake bands under suitable hydraulic controls to effect gear change and control of the direction of rotation of the output or driven shaft from the transmission to the differential for the driving wheels of the vehicle.
Presently manufactured brake bands of the single-wrap type are formed from a strip of sheet steel or similar material and the ends are formed from separate relatively thick forgings, castings or stampings which are suitably secured to the strap of material by spot welding or similar means. Each brake band has an actuation or apply end for an apply piston and a reaction end which is operatively connected to a reaction member in the transmission. Various types of automatic transmissions utilize different types of reaction members. Some reaction members may be of the tangential type which have a stationary plunger or stop member acting against an anchor end of the brake band, while others may be of the reaction pin type where the pin extends perpendicular to the clutch drum and strap and extends into a suitable opening in the anchor bracket for the band.
Where a reaction pin is used to form a reaction member in the transmission, a "volcano" type reaction bracket is often provided which consists of an extruded opening extending radially outwardly from the reaction bracket of the band or a bushing that is secured to the bracket at an opening therein to receive the free end of the reaction pin providing the stationary end of the brake band during use of the band in the automatic transmission. The opposite or apply end of the band is provided with an apply bracket which cooperates with the end of an apply plunger in the transmission that is hydraulically controlled to urge the band ends together to tighten around the clutch drum and stop the rotation of the drum or otherwise alter the rotation of the drum or other member to change the gear ratio or alter the direction of rotation of the output shaft.
Due to assembly tolerances in the transmission assembly and/or testing facilities, the reaction brackets can be subjected to high stress which may result in premature failure during testing or operation of the transmission. To overcome the possibility of any premature failures of the bands or brackets associated therewith, the present invention relates to a novel method of manufacture of the brake band and the brackets therefor such that the strength of the bracket is increased and stress reduced so that failure of the bracket will be lessened and possible rejection of the bands overcome.